Functional Additive Incorporation Enhances the Performance of Semi-Transparent Perovskite Solar Cells

Semi-transparent perovskite solar cells (ST-PSCs) have shown great potential in building-integrated photovoltaics. However, the performance of ST-PSCs is still far from achieving their true potential. Herein, a functional additive, [4-(trifluoromethyl)phenyl] sulfonyl chloride (TFBSC), is incorporated into the perovskite precursor solution to regulate the crystallization process and reduce defects in the perovskite films. The addition of TFBSC improves the perovskite film morphology and increases the charge carrier lifetime and photoluminescence quantum efficiency, compared with the control perovskite films. As a result, the champion device modified with TFBSC shows a power conversion efficiency (PCE) of 14.75% with a light utilization efficiency (LUE) of 3.92%, whereas the control device shows PCE and LUE values of 10.71% and 2.96%, respectively. Moreover, the unencapsulated TFBSC-modified device retains ∼90% of its initial PCE after 1500 h of storage under ambient conditions (relative humidity of ∼30%–40%). These findings could provide new avenues to develop high performance ST-PSCs for smart building applications.